فَـ«سَعْدَانٌ» اسْمُ نَبْتٍ مُنْصَرِفٌ؛ لِعَدَمِ الْعَلَمِيَّةِ.
Translation: Saʿdān is the name of a plant and is fully declinable because it lacks proper-name status.
Merely ending in -ān is not sufficient. Here the word denotes a kind of plant, not a particular person’s proper name.